The term automation supplier usually means an inductive proximity sensor or metal sensor – the inductive sensor is regarded as the commonly utilised sensor in automation. There are actually, however, other sensing technologies which use the term ‘proximity’ in describing the sensing mode. Included in this are diffuse or proximity photoelectric sensors that utilize the reflectivity in the object to improve states and ultrasonic sensors designed to use high-frequency soundwaves to detect objects. Many of these sensors detect objects that happen to be in close proximity towards the sensor without making physical contact.
Probably the most overlooked or forgotten proximity sensors that you can buy may be the capacitive sensor. Why? Perhaps this is due to they have a bad reputation dating back to to after they were first released years back, as they were more prone to noise than most sensors. With advancements in technology, this has stopped being the case.
Capacitive sensors are versatile in solving numerous applications and will detect various types of objects for example glass, wood, paper, plastics and ceramics. ‘Object detection’ capacitive sensors are easily recognized by the flush mounting or shielded face of the sensor. Shielding causes the electrostatic field to be short and conical shaped, much like the shielded version of the proximity sensor.
Just since there are non-flush or unshielded inductive sensors, there are also non-flush capacitive sensors, as well as the mounting and housing looks exactly the same. The non-flush capacitive sensors have got a large spherical field that allows them to be used in level detection applications. Since capacitive sensors can detect virtually anything, they are able to detect levels of liquids including water, oil, glue and so on, and so they can detect levels of solids like plastic granules, soap powder, dexqpky68 and just about everything else. Levels may be detected either directly where the sensor touches the medium or indirectly in which the sensor senses the medium via a nonmetallic container wall.
With improvements in capacitive technology, sensors happen to be designed that will make amends for foaming, material build-up and filming of water-based highly conductive liquids. These ‘smart’ capacitive sensors are derived from the conductivity of liquids, and they also can reliably actuate when sensing aggressive acids such as hydrochloric, sulfuric and hydrofluoric acids. Furthermore, these sensors can detect liquids through glass or plastic walls approximately 10 mm thick, are unaffected by moisture and require virtually no cleaning over these applications.
The sensing distance of fanuc module depends upon several factors like the sensing face area – the greater the better. The following factor may be the material property from the object being sensed or its dielectric strength: the larger the dielectric constant, the higher the sensing distance. Finally, the size of the target affects the sensing range. Just as having an inductive sensor, the target will ideally be equal to or larger in proportion in comparison to the sensor.
Most capacitive sensors possess a potentiometer to allow adjustment from the sensitivity of your sensor to reliably detect the objective. The maximum quoted sensing distance of the capacitive sensor is founded on metallic target, and therefore there is a reduction factor for nonmetal targets.
Although capacitive sensors can detect metal, inductive sensors ought to be useful for these applications for max system reliability. Capacitive sensors are ideal for detecting nonmetallic objects at close ranges, usually lower than 30 mm and also for detecting hidden or inaccessible materials or features.